Hello!

I am failing to create a Zephyr project for Eclipse with C++ support.
Is there a working example or guide I can use as reference to set this up?
My end goal is to use Zephyr + nRF SDK in C++ with debugging in any IDE, preferably SEGGER or Eclipse.

After importing project "hello_world", Eclipse underlines function "printk" in red:
    ==> Function 'printk' could not be resolved <==
    ==> Symbol 'CONFIG_BOARD' could not be resolved <==

Here's the steps I follow to setup the project:
    Toolchain:
        Zephyr 2.0.0
        west v0.6.0
        ninja 1.9.0
        cmake 3.15.2
        Eclipse 4.12 + GNU MCU 4.5.1
    
    Edit prj.conf and .config:
        CONFIG_PRINTK=y
        CONFIG_STDOUT_CONSOLE=y
        CONFIG_NEWLIB_LIBC=y
        CONFIG_LIB_CPLUSPLUS=y
    
    Run:
        west build -b nrf52840_pca10056 C:/embedded/zephyrproject/zephyr/samples/hello_world -- -G"Eclipse CDT4 - Ninja" -D_ECLIPSE_VERSION=4.12
        One warning:
            <...>
            [18/98] Building CXX object CMakeFiles/app.dir/src/main.cpp.obj
            cc1plus.exe: warning: command line option '-Wno-pointer-sign' is valid for C/ObjC but not for C++
    
    Import project into Eclipse
        Error in main.cpp:
        Function 'printk' could not be resolved
    
    Also tried:
        set (CMAKE_CXX_STANDARD 11) in CMakeLists.txt
        Manually add "__cplusplus=201402L" as a symbol in Eclipse (cmake does not generate such symbol in .cproject)
        Force boilerplate.cmake to call eclipse_cdt4_generator_amendment with work mode = 2 (.cproject with __cplusplus)
    
Thanks!

"leonardomt via Lists.Zephyrproject.Org"
<leonardomt=gmail.com@...> writes:

Hello!

Hi again!

I am failing to create a Zephyr project for Eclipse with C++ support.
Is there a working example or guide I can use as reference to set this up?
My end goal is to use Zephyr + nRF SDK in C++ with debugging in any IDE, preferably SEGGER or Eclipse.

After importing project "hello_world", Eclipse underlines function "printk" in red:
==> Function 'printk' could not be resolved <==
==> Symbol 'CONFIG_BOARD' could not be resolved <==

Here's the steps I follow to setup the project:
Toolchain:
Zephyr 2.0.0
west v0.6.0
ninja 1.9.0
cmake 3.15.2
Eclipse 4.12 + GNU MCU 4.5.1

Edit prj.conf and .config:
CONFIG_PRINTK=y
CONFIG_STDOUT_CONSOLE=y
CONFIG_NEWLIB_LIBC=y
CONFIG_LIB_CPLUSPLUS=y

I copied these into samples/hello_world/prj.conf, but:

Run:
west build -b nrf52840_pca10056
C:/embedded/zephyrproject/zephyr/samples/hello_world -- -G"Eclipse
CDT4 - Ninja" -D_ECLIPSE_VERSION=4.12

I can't reproduce this on my Arch Linux machine with
ZEPHYR_TOOLCHAIN_VARIANT=gnuarmemb, toolchain version
gcc-arm-none-eabi-7-2018-q2-update.

The build finishes successfully for me, and works when I flash it to my
board.

What toolchain are you using? Can you try with gnuarmemb?

https://docs.zephyrproject.org/latest/getting_started/toolchain_3rd_party_x_compilers.html#gnu-arm-embedded

One warning:
<...>
[18/98] Building CXX object CMakeFiles/app.dir/src/main.cpp.obj
cc1plus.exe: warning: command line option '-Wno-pointer-sign' is valid for C/ObjC but not for C++

Import project into Eclipse
Error in main.cpp:
Function 'printk' could not be resolved

Also tried:
set (CMAKE_CXX_STANDARD 11) in CMakeLists.txt
Manually add "__cplusplus=201402L" as a symbol in Eclipse (cmake does not generate such symbol in .cproject)
Force boilerplate.cmake to call eclipse_cdt4_generator_amendment with
work mode = 2 (.cproject with __cplusplus)

BTW, since you mentioned Segger and you're using nRF:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/gs_programming.html#building-with-ses

Best,
Marti

Thanks!

Hi and thanks for your prompt response!

I tried both toolchains, gnuarmemb and zephyr.

I can successfully load a zephyr project *without cpp support* into Segger (as in the link) or Eclipse and compile, flash and debug just fine.
Also, you are right in that everything works as expected when using the command line, no matter if the project is c or cpp.

The issue only occurs when you use Eclipse to import a project that requires cpp support:
Eclipse wont recognize some functions (such as printk) and some symbols, instead it will highlight them as if they were not declared anywhere.

Just to make sure I understood correctly, you successfully built the project (the cpp version; main.c --> main.cpp), but did you import it into Eclipse and got no errors after indexing finished?

I read that Eclipse has two separate tools for indexing and resolving symbols/function so I wonder if this error has anything to do with the configuration in Eclipse as opposed to the cmake generator. Another likely situation is that I am not setting things right... either way, help is appreciated!

Thanks!
Leo

"leonardomt via Lists.Zephyrproject.Org"
<leonardomt=gmail.com@...> writes:

Hi and thanks for your prompt response!

I tried both toolchains, gnuarmemb and zephyr.

I can successfully load a zephyr project *without cpp support* into Segger (as in the link) or Eclipse and compile, flash and debug just fine.
Also, you are right in that everything works as expected when using the command line, no matter if the project is c or cpp.

The issue only occurs when you use Eclipse to import a project that requires cpp support:
Eclipse wont recognize some functions (such as printk) and some symbols, instead it will highlight them as if they were not declared anywhere.

Just to make sure I understood correctly, you successfully built the
project (the cpp version; main.c --> main.cpp), but did you import it
into Eclipse and got no errors after indexing finished?

No, sorry, I just built it on the command line.

I read that Eclipse has two separate tools for indexing and resolving
symbols/function so I wonder if this error has anything to do with the
configuration in Eclipse as opposed to the cmake generator. Another
likely situation is that I am not setting things right... either way,
help is appreciated!

I'm not an Eclipse user, sorry :(. It does sound like there's something
wrong with the way either linking or symbol resolution is going on in
Eclipse, though.

Sorry I couldn't be more help. I thought you were seeing this issue on
the command line.

Marti

Thanks!
Leo